Exposure to radon-222 has been associated with excess risk of lung cancer in underground miners and the general population. Radon enters the body primarily through inhalation and ingestion. Although the lung is the primary target organ for radon, other parts of the body may be exposed to circulating radon and decay by-products. The role of radon in the development of cancers other than lung cancer is not well studied, especially in children. The effects of alpha radiation exposure during pregnancy and early childhood are not known. We studied the risk of various selected types of cancer using mortality data collected between 1978-1982 and measurements of groundwater radon concentration previously collected in two states, North Carolina and Maine. In adults, cancer sites of interest were cancers of the upper respiratory tract, cancers of the gastrointestinal tract, the leukemias, bone cancer and female breast caner. In children aged less than 15 years, selected cancers included leukemia, brain cancer, soft tissue sarcomas, and bone cancer. County mean radon values in North Carolina were calculated and ranged from 0 to 10,692 pCi/1. These values were ranked and divided into tertiles. Age-sex-adjusted mortality rates were calculated for each cancer site in each radon group. Studies are nearing completion in North Carolina and are ongoing in Maine. Initial results from this study suggest the need to consider cancer sites other than lung cancer in relation to radon exposure.